Organic light emitting diodes (hereinafter referred to as OLED) panels have been applied widely due to their advantages of light weight, thin thickness, low power dissipation, pure color, wide viewing angle, and flexibility as compared to liquid crystal panels.
A bottom-emitting OLED panel known by the inventor adopts a white light OLED and color filter on array (hereinafter referred to as COA) technology, that is, the bottom-emitting OLED panel adopts a white light OLED and a COA substrate. The manufacturing process of the bottom-emitting OLED panel comprises: firstly forming an array substrate unit on the glass substrate through array process, then performing color filter process on the array substrate unit so as to incorporate the color filter on the array substrate unit, thereby forming a COA substrate through the two process steps, and then manufacturing an electroluminescence layer (hereinafter referred to as EL layer) on the color filter, and finally forming the OLED panel by encapsulation. Light emitted from the EL layer transmits the color filter, the array substrate unit and the glass substrate, and is perceived by an observer. Therefore, the above-mentioned OLED panel is referred to as bottom-emitting structure OLED panel or bottom-emitting OLED panel.
In order to relieve influence of reflected environment light, a polarizer sheet is generally attached to the bottom-emitting OLED panel at the observer side. However, the polarizer sheet would filter out 60% or so from exiting light, resulting in low light utilization. Without a polarizer sheet, although the light utilization is high, the metal layers such as gate layer, source/drain layer and active layer in the COA substrate could reflect environment light, hence reducing the contrast and color gamut of the bottom-emitting OLED panel and impacting the display effect of the bottom-emitting OLED panel. Therefore, how to provide a bottom-emitting substrate with high light utilization capable of relieving influence of reflection of ambient light becomes a concern of those skilled in the art.